The electromagnetic wear particle detector has been widely studied due to its prospective applications in various fields. In order to meet the requirements of the high-precision wear particle detector, a comprehensive method of improving the sensitivity and detectability of the sensor is proposed. Based on the nature of the sensor, parallel resonant exciting coils are used to increase the impedance change of the exciting circuit caused by particles, and the serial resonant topology structure and an amorphous core are applied to the inductive coil, which improves the magnetic flux change of the inductive coil and enlarges the induced electromotive force of the sensor. Moreover, the influences of the resonance frequency on the sensitivity and effective particle detection range of the sensor are studied, which forms the basis for optimizing the frequency of the magnetic field within the sensor. For further improving the detectability of micro-particles and the real-time monitoring ability of the sensor, a simple and quick extraction method for the particle signal, based on a modified lock-in amplifier and empirical mode decomposition and reverse reconstruction (EMD-RRC), is proposed, which can effectively extract the particle signal from the raw signal with low signal-to-noise ratio (SNR). The simulation and experimental results show that the proposed methods improve the sensitivity of the sensor by more than six times.

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According to the on-line monitoring sensor of mechanical devices, the transient characteristics of the magnetic field and induced voltage in the coils during the process of the ferromagnetic wear particle getting through the inductive wear particle sensor were simulated by a 2-D model of finite element method (FEM) built for coils of the sensor using the nonlinear FEM software Jmag Designer 10.4. The material of the coils and particle and input voltage were taken into account. Simulation results reveal the variation law of magnetic density and induced voltage of the induced coil during the particle movement, and obtain the conclusion which is induced voltage of the induced coil is proportional to the turns of induction coil, and is also proportional to the operating speed of the particle. The research results play an important guiding role in the development of inductive particle sensor.